The Wills Act 1837 (as amended) prescribes certain formalities without which a will cannot be valid. In short, a will must be signed, the testator must have intended to give effect to the will by signing it and the will must be witnessed. The absolute need to comply with these technicalities has long been hard-wired into lawyers advising private clients.

So many practitioners were surprised by the Supreme Court’s recent decision in Marley v Rawlings (2014 UKSC 2).

Mr and Mrs Rawlings decided to make identical wills, each leaving everything to the other with a substitutional gift to Mr Marley. Instead of executing their own wills, each by mistake executed the wrong one. The mistake came to light when Mr Rawlings, the surviving spouse, died. If the will he had signed was valid, his estate went to Mr Marley. If it was invalid, he was intestate and his estate would pass automatically to his sons.

Mr Rawlings had signed his wife’s will. How could the will be valid and could the court give effect to his intentions?

There is a statutory provision (s.20 Administration of Justice Act 1982) which allows for mistakes in a valid will to be rectified if the court is satisfied that the document fails to carry out the testator’s intentions on account of a clerical error. Mr Marley applied to rectify the will.

Lord Neuberger said that the document was a will capable of rectification because Mr Rawlings had signed it with the intention of it being his last will and testament, and it had been witnessed. The fact that the will he had signed referred to his wife’s estate did not therefore affect the validity of the will; it’s lack of sense was a matter for construction or rectification.

The Supreme Court held that this was a classic case for rectification because the testator’s intentions were clear. The necessity for wholesale transposition of one will into another did not mean that the changes were too extreme to permit rectification. The court found that giving someone the wrong document to sign could amount to a “clerical error” as required by s20. And so rectification was allowed.

The case is notable for the shift away from a purely technical approach to the validity and interpretation of wills. Lord Neuberger said “Whether the document in question is a commercial contract or a will, the aim is to identify the intention of the party or parties to the document by interpreting the words used in their documentary, factual and commercial context.”

The decision is to be welcomed as sensible and just; it may, however, make it harder to advise in relation to contested wills as some of the old certainties may have been removed. It will be interesting to watch how future cases develop.”